DELL MD3220 사용자 설명서

Configuration: Disk Groups and Virtual Disks

hot spare physical disk. To make sure that enclosure loss protection is not 

affected, you must replace a failed physical disk to initiate the copyback 

process. 
The virtual disk remains online and accessible while you are replacing the 

failed physical disk, because the hot spare physical disk is automatically 

substituted for the failed physical disk.

Enclosure loss protection is an attribute of a disk group. Enclosure loss 

protection guarantees accessibility to the data on the virtual disks in a disk 

group if a total loss of communication occurs with a single expansion 

enclosure. An example of total loss of communication might be loss of power 

to the expansion enclosure or failure of both RAID controller modules. 

Enclosure loss protection is achieved when you create a disk group where all 

of the physical disks that comprise the disk group are located in different 

expansion enclosures. This distinction depends on the RAID level. If you 

choose to create a disk group by using the Automatic method, the software 

attempts to choose physical disks that provide enclosure loss protection. If 

you choose to create a disk group by using the Manual method, you must use 

the criteria specified in Table 9-2.

RAID level 5 

or RAID level 

6

Ensure that all the physical disks in the disk group are located in 

different expansion enclosures. 
Because a RAID level 5 requires a minimum of three physical disks, 

enclosure loss protections cannot be achieved if your storage array has 

less than three expansion enclosures. Because a RAID level 6requires a 

minimum of five physical disks, enclosure loss protections cannot be 

achieved if your storage array has less than five expansion enclosures.

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